1. The Field of the Invention
The present invention is generally directed to optoelectronic devices. More particularly, the present invention is directed to the alignment of a component within an optoelectronic device so as to provide for efficient assembly of the device.
2. The Related Technology
Fiber-optics and optoelectronics are important aspects of modern optical networks because they allow for efficient, accurate and rapid transmission of optical data between various components in the network system. Optical transceiver modules (“transceivers”) are an example of modular components used in optical networks. Such modular component are desirable in optical networks and other fiber optic systems to reduce the cost of manufacturing the system, which cost increases the more customized the system becomes.
Transceivers usually include an input receiver optical subassembly (“ROSA”) and an output transmitter optical subassembly (“TOSA”). The ROSA includes a photodiode for detecting optical signals and sensing circuitry for converting the optical signals to electrical signals compatible with other network components. The TOSA includes a laser for transmitting optical signals and may include control circuitry for modulating the laser according to an input digital data signal as well as a photodetector to monitor laser power. The TOSA has an optical lens for focusing the optical signals from the laser of the TOSA into an optical fiber. Similarly, the ROSA often includes a lens to focus incoming optical signals on the photodiode. Additionally, one end of the transceiver includes pluggable receptacles, pig-tailed connections, or other suitable means for optically connecting the TOSA and the ROSA with other components within a fiber optic network, while another end often includes a connector for connecting with electrical components of a host system or device with which the transceiver communicates.
The photodiode in the ROSA and the laser in the TOSA are examples of optoelectronic semiconductor components. Generally, these optoelectronic semiconductor components are sensitive devices that require mechanical and environmental protection. As such, these optoelectronic components are usually manufactured in packages to provide such protection and to facilitate their incorporation into higher level devices, such as TOSAs and ROSAs.
One such packaging assembly is known as a transistor-outline header or transistor-outline package, referred to herein as a TO package. TO packages are widely used in the field of optoelectronics, and may be employed in a variety of applications. As such, TO packages are often standardized to facilitate their incorporation into components such as transceivers. The TO packages protect the sensitive electrical devices contained therein and electrically connect such devices to external components such as printed circuit boards (“PCB”).
With respect to their construction, the TO packages often include a cylindrical metallic base, also known as a header, with a number of conductive leads extending completely through, and generally perpendicular to, the base. The size of the base is often sized to fit within a specific TO standard size and lead configuration, examples of which include a TO-5 or TO-46. The leads are usually hermetically sealed in the base to provide mechanical and environmental protection for the components contained in the TO package, and to electrically isolate the conductive leads from the metallic material of the base. Typically, one of the conductive leads is a ground lead that may be electrically connected directly to the base.
Various types of electrical devices and optical components, such as the photodiode or laser device, are mounted on an interior portion of the base and connected to the leads to enable their operation. Generally a cap, also known as a can, is used to enclose the interior portion of the base where such electrical devices are mounted so as to form a hermetic chamber that helps prevent contamination or damage to the devices. The specific design of the TO package depends on the optoelectronic component being mounted on the base and the modular component with which the TO package will be used. By way of example, in applications where the optoelectronic component mounted on the base is an optical component, i.e., a laser or photodiode, the cap is at least partially transparent so as to allow an optical signal generated or received by the optical component to be transmitted to or from the TO package. These optical TO can packages are also known as window cans.
In the case of mounting optical components within a window can or other TO package within an optical subassembly, various challenges are often encountered. One challenge deals with accurately positioning the optical component, such as a laser or photodiode, with respect to another component, such as the lens, which may be included in, or proximate to, the package in the optical subassembly. Such positioning is critical to ensure that the optical signals are properly collimated or otherwise focused upon entry to or exit from the optical transceiver module or related device.
In light of the above, a need exists for a means by which a laser, photodiode, or other semiconductor and/or optoelectronic component can be properly positioned in an optoelectronic or other package such that operation of the device in which the component is disposed is optimized.